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Presence of NMDA‐type glutamate receptors in cingulate corticostriatal terminals and their postsynaptic targets
Author(s) -
Wang Hong,
Pickel Virginia M.
Publication year - 2000
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(20000315)35:4<300::aid-syn8>3.0.co;2-c
Subject(s) - neuroscience , postsynaptic potential , glutamatergic , biotinylated dextran amine , glutamate receptor , nmda receptor , excitatory postsynaptic potential , axon , dendritic spine , neurotransmission , chemistry , biology , inhibitory postsynaptic potential , receptor , biochemistry , hippocampal formation
The glutamatergic projection from the anterior cingulate cortex to the medial caudate‐putamen nucleus (CPN) has been implicated in motor and cognitive functions, many of which are potently modulated by activation of N‐methyl‐D‐aspartate subtype of glutamate receptors (NMDARs). To determine the functional sites for NMDAR activation within this circuitry, we combined anterograde transport of biotinylated dextran amine (BDA) from deep layers of the rat anterior cingulate cortex with immunogold labeling of NMDAR subunit, NMDAR1, in the dorsomedial CPN. BDA‐containing axons were seen in patch‐like clusters in a neuropil that showed more uniform immunogold‐silver labeling for NMDAR1. Electron microscopy of these regions showed that BDA‐labeling was present exclusively in axons and terminals, 23% (98 of 421) of which also contained NMDAR1‐immunoreactivity (IR). BDA‐labeled terminals often apposed NMDAR1‐immunoreactive neuronal and glial profiles. These terminals also formed asymmetric excitatory‐type synapses with dendritic spines. Of 155 anterogradely labeled axon terminals forming asymmetric synapses, 34% were with NMDAR1‐labeled, and 66% with unlabeled dendritic spines. These results provide ultrastructural evidence for the involvement of NMDARs in presynaptic regulation of glutamate transmission, and in postsynaptic modulation of the excitability of spiny neurons in patch‐like compartments of the dorsomedial CPN. These dual NMDAR‐mediated actions are likely to play a major role in the acquisition of new behaviors and reward‐related processes that have been associated with cortical input to the striatal patch compartments. Synapse 35:300–310, 2000. © 2000 Wiley‐Liss, Inc.